Monday, December 30, 2013

The Wood Stove Decathlon was a
historic event. It was the first ever attempt to gather a collection of stoves
in the field (literally, in this case) and test them for particulate matter
(PM) emissions.

Norbert Senf, right, with Neils Wittus,
center, and John Ackerly

For something untried until now,
the side-by-side field-testing can claim several firsts.

It successfully
compared stoves within a surprising range of categories including masonry
heaters as well as retrofit kits. The project was a success not only as a media
event but also in advancing the real world testing of wood burning stoves.

Cordwood is an extremely complicated
fuel to get repeatable data with because it is so inherently variable. To add
to the challenge, PM is particularly difficult to measure, even in a
laboratory. While the test results from the Decathlon were not sufficient to
provide PM numbers that allowed comparison with EPA numbers, they did allow a
ranking of the stoves against each other. This is a substantial achievement in
itself.

PM is the wood fuel pollutant of
greatest interest since it causes the most public health concerns. Carbon
monoxide (CO) is another pollutant.It
is created by incomplete combustion like PM, but it is much easier to measure.
It is generally not considered a health hazard in low atmospheric concentrations
outside of densely trafficked urban areas, and eventually oxidizes to CO2 on
its own.

Due to new wood burning emissions regulations in Germany, two new portable instruments for measuring PM in the field were recently developed there. Fortunately, this happened just in time for the Decathlon to try them out. The instruments are limited to the 15-minute test cycle that is mandated in the German regulation, and therefore can only measure what happens during a portion of the burn. Measuring an entire test cycle will certainly be a goal for future Decathlons.

Common wisdom holds that low
carbon monoxide (CO) emissions, which are easy to measure, will also ensure low
PM, which is difficult to measure. The contest results did not bear this out.
The stove with the lowest PM had the second highest CO. For the stove with the
lowest CO, there were 4 stoves with lower PM. To be sure, the data set is
limited. The 15-minute test window did not allow for average values to be
measured over the burn of an entire fuel load.

Repeatability is one of the most
important measures of data quality. Since each stove in the Decathlon received
two (in theory) identical test runs, we can get a brief glimpse here, as well.
Discarding obvious outliers, we see a coefficient of variation (CV) in repeat
runs of 43% on PM, 40% on CO and 7% on efficiency. This compares favorably with
EPA inter-laboratory repeatability studies, where the two stoves with the
largest data sets both came in at 44% CV on PM. For masonry heaters, an MHA
(Masonry Heater Association) laboratory study on repeatability with dimensional
lumber fuel cribs yielded 10% CV on PM, 1.5% on CO, and 0.26% on efficiency.

The repeatability metric provides
a useful baseline for judging data quality in future decathlons. There is an
ongoing fueling protocol debate in the testing community between the
repeatability achievable with fuel cribs, and the real world randomness of
cordwood. EPA testing is currently done with cribs. To get a repeatable EPA
cordwood number may require running a large number of (expensive) laboratory
test runs and taking an average. To date, very little work has been done to
provide data for either side of the debate.

All in all, the Wood Stove
Decathlon was a great effort towards advancing our knowledge about how wood
stove emissions compare in the real world. This was particularly valuable to
see for different classes of appliances with no commonly defined EPA testing
methods.

Valuable lessons and insights were
had for designing a future challenge. Seeing the complex testing issues play
out in real life was a unique educational opportunity for contestants,
organizers, judges, regulators and the testing community itself.

Norbert Senf was one of the ten judges at the Wood Stove Decathlon. He joined early efforts to write
codes and standards, and was a founding member of the Masonry Heater
Association of North America (MHA). He currently chairs the MHA Technical
Committee.

Monday, December 23, 2013

From inception, to announcement, to selecting the teams, to holding the
Wood Stove Decathlon, the Wood Stove Design Challenge unfolded over a 2-year
period.The total cost
came to about $200,000 over those 2 years, and $157,000 of that was in 2013.

In 2013, the Wood Stove Design Challenge cost about $157,000
in direct cash expenses.In addition,
tangible, in-kind donations that we would have otherwise had to pay for
accounted for more than $50,000.The
largest budget items were salaries ($39,000), the tent ($33,000), prize money
($30,000) and testing ($23,000).

Overall, our largest funders were NYSERDA ($47,000), the Osprey
Foundation ($40,000), and the District of Columbia ($10,000).In addition, we had extremely large in-kind
support from ICC Chimney, which was probably in the $20,000 range, the Chimney
Safety Institute of America, the mobile particulate sampling companies Wohler
and Testo, Brookhaven National Lab, Popular Mechanics, Travis Industries and others.

One reason the Alliance was able to hold this competition for a
total cost of $200,000 is that salaries were low, and we kept many expenses to a
bare minimum.If the Alliance were to do
another similar Design Challenge, we would have to plan for a total of about $300,000
over a two year period, and use at least $200,000 of that for the year of the event.

Thursday, December 12, 2013

On October 9, seven states and five environmental groups
sued the EPA for failure to promulgate new emission standards for residential
wood heaters. If EPA had done its job
years ago, as it was obligated to do under the Clean Air Act, the stove
industry and consumers would be far better off today.

An example of the size of wood thatcan be loaded in an outdoor boiler.

Instead, we have all been dragged down by an agency that has
not taken residential wood heating seriously enough. And some of the key outdoor wood boiler
manufacturers have opposed reasonable state and local regulations on their
products, leading to controversies with state air agencies and environmental
groups that could be avoided.

The EPA did develop a voluntary program to help regulate outdoor wood boilers and states started adopting that in 2007. Northeastern states, Indiana and Pennsylvania used that and Washington and Oregon effectively banned them outright. The states where outdo boilers are most popular like Michigan, Minnesota and Wisconsin, failed to use the EPA voluntary program to protect their residents from these polluting devices.

Privately, most people in the wood heating industry agree
that outdoor wood boilers have given us all a black eye.Those devices, particularly concentrated in
the Great Lakes region, are contributing towards a negative view of wood
heating at a time when the public and policymakers could have been developing a
more positive view, as they have in Europe.

But some outdoor boiler manufacturers, while officially
saying that they want to be regulated, have fought in state after state to keep
selling old-fashioned polluting boilers.And now they are fighting the EPA over what they feel are far too
burdensome regulations.

Meanwhile, in Europe, where such technologies don’t exist,
governments are vigorously supporting wood heat technologies through rebates
and incentives.

One reason Europe has been able to incentivize wood heating
is that almost every country has a green label to identify the cleanest and
most efficient stoves and boilers, which gives lawmakers the ability to give
rebates and incentives to the best products.In the US, there is no Energy Star program for wood heaters and industry
has put the brakes on a state initiative to create a green label program.Once we have a green label program, I think
we will start to see the tide turn, with states beginning to shift consumer
purchases towards the cleanest and most efficient wood and pellet stoves and
pellet boilers.

In polluted urban areas, like Denver and Montreal and parts
of the Pacific Northwest, we are likely to see more bans on the new
installation of wood stoves and a shift toward pellet stoves.This may not be ideal, but it is also a reasonable
response.Cordwood isn’t an appropriate energy
solution for lots of people in densely inhabited urban areas, particularly
those that experience weather inversions, when the technology is so dependent
on operators using seasoned wood and giving the appliance enough air.

In coming months, our community will be increasingly in the
public spotlight as these lawsuits against the EPA get underway and we have a
90-day public comment period over the EPA’s long awaited regulations.We are in an era where technology can make
wood and pellet stoves far cleaner, while still being affordable. Many of these stoves were on display the
National Mall at the Wood Stove Decathlon in mid-November.There, policy makers saw what stove engineers
are working on and are capable of creating.They saw first hand that wood heat technology is developing fast and can
be a vital part of our renewable energy future, not just a relic of the past.

Outdoor wood boilers are the most polluting class of
residential wood heaters on the market today, and as such they will be the most
in the news. But the EPA regulations are
still vital in requiring both wood and pellet stoves to become cleaner and more
efficient.Once that happens, public
opinion can begin to shift in a more favorable way towards deploying modern
wood and pellet technology to reduce our reliance on fossil fuel, and shrinking
the divide between US and European policy.

Tuesday, December 3, 2013

The danger of naming a winner at a competition like this is that the many achievements of the non-winners receive little focus. Here we list the top 6 stoves in each category: Overall Performance, Innovation, Affordability, Particulate Matter Emissions, Efficiency, Market Appeal and Carbon Monoxide Emissions. We try to note the trends between stove classes and the stand out performances of stoves that did not win prizes.

The scoring was done by nine judges. Three of the areas -- PM emissions, efficiency and CO emissions -- were scored only by the testing equipment, meaning the judges had no discretion to change the grade of the stoves for those three areas. Each stove was tested at least two times. For more on scoring see: http://forgreenheat.blogspot.com/2013/11/how-stoves-are-scored.html

The Grand prize went to a finely tuned, naturally drafting catalytic wood stove without any electronic controls. In fact, the winning Woodstock Soapstone hybrid is very similar to the design of one of the second place stoves, the Cape Cod by Travis. Wittus is also a naturally drafting steel stove that has a unique downdraft burn into a lower chamber. Technically, this is a non-cat stove, but its design has little in common with the traditional non-cat stoves on the market today.

The fourth and fifth top overall stoves were masonry stoves, and while they did not take home any prizes (due to their high pricetags and perceived lack of innovation, as the underlying designs and principles are so old), it is clear that they performed extremely well overall. Two of the top 6 stoves overall had electronic sensors and computers.

The two top innovation scores went to a Danish stove and a German stove. First place went to the Hwam Autopilot stove with its onboard computer and oxygen sensor. If testing lasted many hours, not just 15 minutes, these features would have likely helped the stove receive higher overall points. The stove also alerts the homeowner to the optimum time to reload and how much wood to reload. There is no control on the stove for users to adjust; they can simply load it and leave, knowing that the stove will do the rest.

The IntensiFire claimed the number 3 spot because it is a relatively simple, elegant solution for old, uncertified stoves. And Mulciber, the University of Maryland stove, took 5th place with a pressurized, fan driven combustion chamber and co-axial stack.

Tom Morrissey’s hybrid Ideal Steel from Woodstock Soapstone is clearly a great value given its size, BTU output and performance. The company has committed to retail it for $2,000 and hopefully that doesn’t mean it’s a loss leader for the company. The Walker stove, a hybrid rocket stove that can be made with more thermal mass, also impressed the judges and has lots of potential to get on the market for less than $2,000.

This is the one area that the SmartStove appears in the top 6 rankings for its control system that can automate virtually any non-catalytic stove, significantly reducing its overall emissions for about $200 on top of the stove price.

In the emissions category, seen by many experts as the key goal of high performing stoves, the underdog team from the University of Maryland took a surprising first place with a least one run where the PM 2.5 particulates were so low they were barely measurable. The students used a home-made catalyst and a unique self-cleaning particulate trap to achieve these results.

Again, the masonry stoves did very well along with the other catalytic stoves. The Travis Cape Cod has the lowest PM measurement of any certified wood stove at .45 grams an hour, one tenth of the more stringent Washington State limit, when tested with dimensional lumber.

All the masonry stoves performed extremely well in the efficiency category, even though the top spot went to the downdrafting German Wittus stove that has a relatively small firebox. Since efficiency is measured using a stack heat loss method, the masonry stoves could lose most of their heat to the masonry mass before exiting the chimney. The University of Maryland’s Mulciber stove often had stack temperatures around 200 degrees, half that of some of the other stoves.

What is surprising here is that neither the Woodstock Soapstone nor the Travis placed in the top 6, even though they have 3rd party efficiency testing that rates them around 82% in the EPA wood stove list. This could mean that these other stoves could hit efficiencies even higher, around 84 or 85% using the EPA’s B415.1 test, or it may simply mean that the efficiency testing and methodology at the Decathlon favored masonry stoves or was not good enough to measure very minor differences between very efficient stoves.

The more polished stoves that were already in production won out here, with the catalytic and masonry stoves vying again for top spots. The judges appeared to vote based on what they thought was likely to appeal to the average consumer based on aesthetics, without regard to price.

Again, this category was a battle between the catalytic stoves and the masonry stoves, with the catalytic stoves taking the top spots. The University of Maryland team also used a catalyst but insufficient air on at least one run hurt their CO levels. It is noteworthy that the IntensiFire made it into the top 6, given that it used a very simple, affordable change to an old, uncertified stove.

Wednesday, November 20, 2013

Catalytic,
Masonry and Electronically Controlled Stoves Show High Results in Testing

Washington
D.C. – In an international competition to significantly reduce pollution from
wood stoves on the National Mall, one finalist, Woodstock Soapstone of New
Hampshire, won first prize of $25,000. Two other teams, Travis of Washington
State and Wittus of New York, were awarded $5,000 each. The teams were recognized for all around
performance in efficiency and emissions, affordability, consumer appeal and innovation. Members of Congress Dan Benishek
(R-MI), Chris Van Hollen (D-MD), Jared Huffman (D-CA), Paul Tonko (D-NY) took
part in the awards ceremony.

The Woodstock Soapstone Team

In
accepting the first prize of $25,000, Woodstock Soapstone owner Tom Morrissey announced that he was giving part of the prize money to two other teams -
Walker Stove and Intensi-Fire - who had come to the Decathlon on a shoestring
and needed funds for their work. Travis donated their $5,000 to the Alliance for Green Heat to help pay for the expenses of the Decathlon.

“These
award-winning technologies are part of the solution for millions of Americans
to reduce their reliance on fossil heating fuels,” said John Ackerly Founder and
President of the Alliance for Green Heat, which organized the Wood Stove
Decathlon. "We'd like to thank all the teams for participating and contributing to an ongoing educational effort to help the US government appreciate the potential of cleaner and more efficient wood heating," Ackerly added.

Competitors represented a wide range of wood stove technologies. Two of the top three winners were catalytic hybrid stoves.While the three masonry stoves did not take home
prizes, they had some of the highest scores in efficiency and cleanliness.

The
Wittus Twin Fire, that was tied for second prize overall, scored highest in the efficiency
category. Travis’s Cape Cod Hybrid, which also tied for second overall, scored highest in consumer appeal and for low carbon monoxide. The Hwam 3630 IHS scored highest in innovation, with its oxygen
sensor and control device that alerted the consumer when and how much wood to
reload. The Woodstock Soapstone, which won the Grand Prize, also won in the affordability category. And the University
of Maryland’s stove, the Mulciber, won in the lowest particulate matter
category.

The overall
ranking of stoves was:

WOODSTOCK SOAPSTONE

1

TRAVIS

2

WITTUS

2

INTER-CONTINENTAL

3

TILE STOVE

3

HWAM

3

TULIKIVI

4

INTENSI-FIRE

5

MULCIBER

5

WALKER STOVES

6

SMART STOVE

7

KIMBERLY

8

The competition differed from EPA tests of
wood stoves in several key respects to more closely resemble how consumers use
stoves.First, the stoves in the competition were tested using
cordwood instead of 2x4s and 4x4s. Second, technicians loaded stoves with
12 pounds of wood per cubic foot of firebox space for the first round of
testing, whereas EPA only uses 7 pounds of wood per cubic foot.

Two of
the stoves made small amounts of electricity and four had electronic control
systems.More detailed analysis
will be forthcoming. The primary funders of the Wood Stove Decathlon are
NYSERDA, the Osprey Foundation, the District of Columbia Urban Forestry
Administration, the US Forest Service, the
West Penn Power Sustainable Energy Fund and the Arbolito Foundation.

# # #

The
Alliance for Green Heat is an independent non-profit that promotes
high-efficiency wood heating as a low-carbon, sustainable and affordable
heating solution. The Alliance seeks to make wood heat a cleaner and more
efficient renewable energy option, particularly for those who cannot afford
fossil fuel heat.